I have a broken pedal that sounds amazing, how do I re create it?

Started by dizzy, May 24, 2016, 04:31:08 AM

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dizzy

I had a TS808 clone, that sounded just like a good tube screamer should.

I was at a band practice in a garage, ran out of battery, so I grabbed a multi power setting wall wart and set it to 9v.

All was good for about 15 mins, then the power supply burnt out and died.

Since then the pedal has sounded completely different, it still works but sounds nothing like a tube screamer should and way more gain on tap too, it is now my go to lead boost. I would like to make another one, but I have no idea how to re-create what is essentially a broken pedal.

Any suggestions?

Elijah-Baley

Is your clone a commercial replica or a homemade pedal?

It's simple. If it is a commercial replica you could search on the web the schematic, you could find it.
If it an homemade you need to know if it is the original schematic or a slightly modded schematic. In both the cases you could got your pedals's schematic because the original is the original, and many mods are rather commons and easy.

Give us more information about your pedal.
«There is something even higher than the justice which you have been filled with. There is a human impulse known as mercy, a human act known as forgiveness.»
Elijah Baley in Isaac Asimov's The Cave Of Steel

balkanizeyou

Hard to say exactly what happened to your power supply, but if it shorted itself, my guess would be that the op-amp fried itself a little, which would result in a weird sound (I overheated a tl072 once during soldering, and as a result the circuit had a higher gain, but also produced more distortion). I don't think it would be easy to recreate these conditions

Elijah-Baley

Sorry, I misunderstood.
Also I think it's hard to recreate the sound of a broke pedal.
You could start to verify what is the component which doesn't ok. Maybe is the IC. Then you should make some experiments after check voltages, frequencies... Too much for me.
An audio probe could be useful, especially if you can compare this failed circuit with a good one.
I can't be helpful.
«There is something even higher than the justice which you have been filled with. There is a human impulse known as mercy, a human act known as forgiveness.»
Elijah Baley in Isaac Asimov's The Cave Of Steel

Jamdog

My guess is the ICs are somewhat altered. 
Try to swap them to known working ones and see how it sounds,  if you identify what's different,  you may be able to recreate the change.

For all we know,  you may have just fried one resistor that changes the whole sound...
-Jamdog

Groovenut

Let's say just for speculation that the opamp is fine but the power supply over heated one of the bias resistors and it now measures half of what it did, causing the bias to be skewed to one side and now the opamo clips the rail in addition to the clipping diodes resulting in more distortion.

Measure the voltages and post them. Something might come to light.
You've got to love obsolete technology.....

duck_arse

^^ like jamdog says.
^ like groovenut says.

if something obviously off comes from the voltage readings, you then need to test each associated part to find which is doing the do. if nothing obvious from the voltages, test all the parts to seee which is what is different from its markings.
granny at the G next satdy.

R.G.

I have several friends who are amplifier repair technicians. They all have told me one variant of the following:

A fellow came in with his amp the other day, telling me that the amp burned out on him in the middle of a gig. He then said that just before it burned completely out, it sounded amazingly good. Could I fix it so it would sound that way all the time and not burn out?

R.G.

In response to the questions in the forum - PCB Layout for Musical Effects is available from The Book Patch. Search "PCB Layout" and it ought to appear.

thermionix

Quote from: R.G. on May 24, 2016, 12:10:19 PM
I have several friends who are amplifier repair technicians. They all have told me one variant of the following:

A fellow came in with his amp the other day, telling me that the amp burned out on him in the middle of a gig. He then said that just before it burned completely out, it sounded amazingly good. Could I fix it so it would sound that way all the time and not burn out?

Ha!  Yep, I've heard the same thing.  Things always sound best right before they blow up.  In amps I think it's the power tubes red-plating, and they sound good with that high current.  Can't be sustained though.

Years ago I was given an old alnico 12" (Utah?) speaker, and I wanted to hear what it sounded like.  The only operational amp I had at the time was a 100W plexi reissue.  I thought, well, if I only barely turn the volume on....  Well, the speaker lasted a few short seconds, but MAN did it sound cool!

robthequiet

Any chance you could upload a sound sample somewhere? Might give us a clue as to how to replicate.  8)

stallik

Long while ago, I built a Mayqueen. Turned out the J201 came from a dodgy source, was extraordinarily difficult to bias but when done sounded amazing though nothing like a Mayqueen. I had 2 such transistors, both from the same supplier, both with the same effect.

I wanted to find a supply of similar, dodgy trannies and embarked on a long journey to find some. I was unsuccessful. It's a long dark road. Just sayin ;)
Insanity: doing the same thing over and over again and expecting different results. Albert Einstein